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Unread 03-03-2011, 05:29 PM   #16
4.7stroker
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1988 YJ Wrangler 
 
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Yes. the baffle, is a device to prevent oil from exiting the valve cover through the pcv/ccv system. Simply remove the screws that keep it in place and clean the bejesus out of everything.

Dwayne

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Unread 03-04-2011, 04:11 PM   #17
Rynfw100
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Quote:
Originally Posted by 4.7stroker View Post
Yes. the baffle, is a device to prevent oil from exiting the valve cover through the pcv/ccv system. Simply remove the screws that keep it in place and clean the bejesus out of everything.

Dwayne
I took the Baffles off, and to my surprise, they were completely clean. I asked my Father, the one who messed with the valve cover before, if he had cleaned them when he took the Valve Cover off, and he said that he had. So it's not the Baffles, which is why we originally thought it was something a little more complicated.

Any other ideas? Here's what we have so far:
  • The Side Crankcase Vacuum line is clean, and the vacuum line clean.
  • Valve Cover is Clean, Baffles included.
  • Engine runs Fine, No Skips.
  • Exhaust is good, no burned marks, I do have a small leak on the underside, need to patch it up... but it Shouldn't Cause a blowback. The Exhaust does smell when I start it up, but it goes away after a minute or two of driving.

Last edited by Rynfw100; 03-04-2011 at 05:48 PM..
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Unread 03-05-2011, 09:49 AM   #18
Rynfw100
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Bump, cause I'd really like to get this problem out of the way.

Thanks
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Unread 03-05-2011, 01:11 PM   #19
Cooter92YJ
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I remember a post in either "I made a...", or "cheap fixes" here in the YJ Technical section, that dealt with this problem. The op made a "scrubber", where the hose went to a homemade pvc cannister he mounted on the firewall then on to the intake, and the captured oil drained back into valve cover. Try to do a search, or maybe someone else has a better memory than mine and point you to it faster.
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Unread 03-05-2011, 02:31 PM   #20
Rynfw100
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Quote:
Originally Posted by dsjohnson View Post
I remember a post in either "I made a...", or "cheap fixes" here in the YJ Technical section, that dealt with this problem. The op made a "scrubber", where the hose went to a homemade pvc cannister he mounted on the firewall then on to the intake, and the captured oil drained back into valve cover. Try to do a search, or maybe someone else has a better memory than mine and point you to it faster.
Thanks for the suggestion.

However I'd rather not avoid the problem, want to get it done right the first time if I'm going to do any work.

Although I may need to keep this tip in mind if fixing the problem involves a total rebuild.
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Unread 03-05-2011, 04:41 PM   #21
4.7stroker
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Have you performed a wet/dry compression test and a leak down test? These will tell you the condition of your internals. Blow by is caused by combustion gasses getting by something rings or valves are normal. These gasses pressurize the crank case and oil gets blown out. As long as there is sufficent vacuum to draw these gasses out and leave the crankcase at a slight vacuum there is not a problem. If the pcv ccv system is not operating right or the volume of gasses is too much you will have blow by. If it is the latter the only fix is a rebuild.

Dwayne
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Unread 03-06-2011, 06:06 PM   #22
Rynfw100
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Quote:
Originally Posted by 4.7stroker View Post
Have you performed a wet/dry compression test and a leak down test? These will tell you the condition of your internals. Blow by is caused by combustion gasses getting by something rings or valves are normal. These gasses pressurize the crank case and oil gets blown out. As long as there is sufficent vacuum to draw these gasses out and leave the crankcase at a slight vacuum there is not a problem. If the pcv ccv system is not operating right or the volume of gasses is too much you will have blow by. If it is the latter the only fix is a rebuild.

Dwayne
We checked the Vacuums while the engine was running, the 3 on the intake at least, and they all had a considerable suction and adverse effect on the idle when unplugged.

Next, we did a dry compression test, couldn't find a place to rent/borrow a leak down test from. Let's say that the plug closest to the firewall is 4 and the closest to the front of the Jeep is 1. Cylinders 1-3 all had a compression of 125-6, while Cylinder 4 had a compression of 120.

The only other thing that we did was re-space the plugs, which we noticed were nicely ashen gray, and the spacing was too wide.
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Unread 03-08-2011, 04:48 PM   #23
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Unread 03-09-2011, 10:22 PM   #24
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Anybody have an idea on what the compression readings mean from the dry test? Further details above ^^^
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Unread 03-28-2011, 02:17 PM   #25
kelti819
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they are good that is the usual readings on a dry test.
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Unread 03-28-2011, 03:36 PM   #26
steelman10
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I had the same problem so I switched to a 350 V8 and it seems to run fine now
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Unread 03-16-2013, 08:23 AM   #27
StevilKnievil
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It is perfectly normal to have oil on your air filter, as far as mopars design team is concerned. It is a normal part of the ccv system these engines employ. As far as your piston rings are concerned, if your compression tests were all within nop with no considerable variations and it is not burning oil, they are fine and not to be worried about. As for your friends advice on pistons not touching oil, stop taking advice from this friend. The head should not come in contact with oil, that's what the rings are designed for. At 140k you shouldn't really be too concerned with overhauling the block. If you smell oil burning in the exhaust and notice when it isn't cold out that there is still significant "smoke" coming from the tail pipe then it would be something to consider. But, until then, keep calm and keep wheelin'!
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Unread 03-17-2013, 11:24 AM   #28
sbonilla75
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If there is oil in your air filter follow the line from the air filter to the pcv valve on the front of the valve on your engine. Unscrew the nipple at the end of the hose and see if it is stopped up. We had a mechanic tell us it would cost $800 to fix cleaned the pcv valve and no more blowback or leakage .
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Unread 03-17-2013, 02:32 PM   #29
Que89YJ
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Clean both hoses as well. Chances are the valve cover has crud built up under it if it has been doing it for a while. Clean the tubes and the inside of the valve cover too.
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2.5l , blow by , engine , oil , YJ
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